AOS Classification Committee – North and Middle America Proposal Set 2019-D 21 March 2019 (revised 29 March 2019) No. Page Title 01 02 Split Vermiculated Screech-Owl Megascops guatemalae 02 14 Add Thick-billed Warbler Arundinax aedon to the Main List 03 17 Add River Warbler Locustella fluviatilis to the Main List 04 19 Add European Robin Erithacus rubecula to Main List 05 21 Add Pied Wheatear Oenanthe pleschanka to the Main List 06 23 Add Mistle Thrush Turdus viscivorus to the Main List 07 24 Add Pink-footed Goose Anser brachyrhunchus to U.S. list 08 25 Add Nazca Booby Sula granti to the U.S. list 09 27 Add Black-backed Oriole Icterus abeillei to the U.S. list 10 29 Add White-cheeked Starling Spodiopsar cineraceus to the Appendix 11 31 Add House Swift Apus nipalensis to the Appendix 12 33 Add Great Black Hawk Buteogallus urubitinga to the U.S. list 13 34 Transfer Budgerigar Melopsittacus undulatus from the Main List to the Appendix 14 36 Reinstate Nesophlox for Calliphlox evelynae and C. lyrura 1 2019-D-1 N&MA Classification Committee p. 256 Split Vermiculated Screech-Owl Megascops guatemalae Note: This proposal follows up on Dan Lane’s proposal (SACC #771) to split the widespread species Megascops guatemalae into two or three species: M. guatemalae and potentially a separate M. vermiculatus would be restricted to Middle America and within NACC territory; and M. centralis from central Panama to western Colombia, which would apply to both the NACC and SACC. We do not consider M. roraimae, which occurs in South America and would be extralimital to the NACC region, because it was not regarded as part of M. guatemalae in AOU 1998. Background: Ridgway (1914) treated Otus guatemalae (Sharpe 1875, Guatemalan Screech Owl) as a species separate from O. vermiculatus (Ridgway 1887, Vermiculated Screech Owl). He noted that O. guatemalae is found from southeastern Mexico, in the states of Veracruz and Oaxaca, southward through Guatemala and Honduras to northern Nicaragua. He wrote that O. vermiculatus resembles O. guatemalae superficially, but that the former has the lower portion of tarsus naked (the feathering shorter toward the lower portion of the tarsus), the tail much shorter, the coloration much more uniform (the upperparts with finer vermiculations and usually without distinct spots or streaks, and the underparts usually more densely vermiculated), and the eyebrow never whitish (always brown or chestnut-rufous). The distribution provided for O. vermiculatus was from Costa Rica and Panama south through western Colombia to western Ecuador. Ridgway (1914) noted that he had not seen specimens from either Colombia or Ecuador. Cory (1918) also treated O. guatemalae as a species separate from O. vermiculatus. He listed the distribution of O. guatemalae as “Southeastern Mexico to Guatemala; West Ecuador?" and that of O. vermiculatus as “Costa Rica to Panama and south through western Colombia to western Ecuador”. Cory also noted that he had not seen specimens from Colombia or Ecuador. Peters (1940) listed all the different forms as subspecies of a single species, O. guatemalae. Peters noted that Chapman (Bull. Am. Mus. Nat. Hist., 63, 1931, p. 64-65) believed O. vermiculatus to be specifically distinct from O. guatemalae on the basis of the relatively shorter tail and tarsus of the former and because there is a specimen from the Paria Peninsula of northeastern Venezuela in the American Museum of the size and proportions of O. guatemalae, indicating that both birds may occur in northern South America. Eisenmann (1955) listed a single species, O. guatemalae, which would be distributed in tropical Middle America and South America. However, he added a note indicating that some considered birds from Costa Rica, Panama, and South America to be a separate species, O. vermiculatus. Under that view, the birds from Mexico to Nicaragua may be called Middle American Screech- Owl. Wetmore (1968), Stiles and Skutch (1979), Hilty and Brown (1986), Ridgely and Gwynne, Jr. (1989), and Howell and Webb (1995) listed a single species, O. guatemalae, and from here on the English name Vermiculated Screech-Owl has been used when O. guatemalae and O. vermiculatus have been considered conspecific. The species’ range extends from NW and E 2 Mexico to N Venezuela, W Ecuador, and Bolivia. However, some authors noted that the birds from Costa Rica and southward are sometimes considered a separate species, O. vermiculatus, from O. guatemalae, which is then called Middle American Screech-Owl. Hilty and Brown (1986) and Ridgley and Gwynne, Jr. (1989) explained that such a split would be based on the fact that the two taxa differ in voice. Hekstra (1982) published descriptions of 24 new subspecies of American Otus. Hekstra considered O. guatemalae (Vermiculated Screech Owl) a superspecies with 19 subspecies divided into six groups: cassini, hastatus, guatemalae, vermiculatus, roraimae, and pacificus. One of the new subspecies he described was O. g. centralis. He included this subspecies within the O. g. vermiculatus group. It is found in Panama east of Chiriquí through Darién into the Serranía de Baudó (Colombia), and perhaps also in adjacent northwestern Colombia (Cordoba, Bolivar, Magdalena), but not on the Pacific side of western Panama. It was described as intermediate in appearance between vermiculatus and guatemalae. All measurements are similar to those of vermiculatus, but the plumage pattern is more similar to that of guatemalae, with coarse streaks, bars and patches, and more reduced vermiculations. Tarsi are bare for less than the lower quarter. AOU (1998) considered O. guatemalae (Vermiculated Screech-Owl) as a single species consisting of two groups, the guatemalae group distributed from southeastern Sonora and southern Tamaulipas south on both slopes of Mexico to Chiapas and the Yucatan Peninsula, and thence south through Guatemala, Belize and Honduras to north-central Nicaragua; and the vermiculatus group locally distributed from northeastern Costa Rica and Panama south to western Colombia. AOU (1998) noted that O. guatemalae [Middle American Screech-Owl] and O. vermiculatus [Vermiculated Screech-Owl] are sometimes treated as separate species because of vocal differences (references in AOU 1998: Sibley and Monroe 1990, Marshall et al. 1991). The Howard and Moore Checklist (Dickinson and Remsen 2013) listed a single species, Megascops guatemalae - Vermiculated Screech Owl, which included nine subspecies (several of which they noted might merit species rank): 1. M. g. hastatus W Mexico (S Sonora and SW Chihuahua to Oaxaca). Includes tomlini. 2. M. g. cassini NE Mexico (S Tamaulipas, SE San Luis Potosí and N Veracruz) 3. M. g. fuscus NE Mexico (C Veracruz) 4. M. g. thompsoni SE Mexico (Yucatan Pen., Isla de Cozumel) 5. M. g. guatemalae SE Mexico (S Veracruz and NE Oaxaca) to Honduras 6. M. g. dacrysistactus NW Nicaragua 7. M. g. vermiculatus Costa Rica to W Colombia and SW Ecuador (El Oro); Sierra de Perijá, Andean slopes and Coastal Range of Venezuela. Includes centralis, inexpectus, and probably pallidus. 8. M. g. roraimae Tepuis and mountains of S and SE Venezuela, N Brazil, SW and S Guyana and Surinam 9. M. g. napensis E slope of Andes from Ecuador to WC Bolivia (N Cochabamba) Mikkola (2014) treated guatemalae and vermiculatus as separate species, and he noted that the two differ vocally and no hybrids between them are known; in addition, they are geographically 3 separated and differ in plumage. Mikkola also treated centralis as a separate species, and reported that it is unknown whether centralis is sympatric with vermiculatus in eastern Costa Rica. Vallely and Dyer (2018) recognized the single species Megascops guatemalae – (Vermiculated Screech-Owl). They reported that the song of northern Central American populations is a long, hollow, flat, toad-like trill, whereas the song of the southern Central American populations, M. g. vermiculatus (southern Nicaragua to western Panama), is very similar but perhaps slightly higher in pitch. Additionally, the song in central and eastern Panama is shorter and distinctly down-slurred. The authors did not mention it, but this last song variation might refer to centralis. Holt et al. (2019a, b) listed two species: M. guatemalae (including subspecies 1 through 6 from Howard and Moore) and M. vermiculatus (subspecies 7 through 9). They noted that centralis is sometimes recognized as a separate species (range Panama to SW Ecuador) "based primarily on its distinctive voice". Table 1. Summary of the taxonomic history of Megascops guatemalae. Reference Scientific name English name Geographic range Ridgway (1914) Otus guatemalae Guatemalan SE Mexico to N Nicaragua Screech Owl O. vermiculatus Vermiculated Costa Rica to W Colombia Screech Owl and W Ecuador Cory (1918) O. guatemalae Guatemalan SE Mexico to Guatemala Screech Owl O. vermiculatus Vermiculated Costa Rica to W Colombia Screech Owl and W Ecuador Peters (1940) O. guatemalae Not included SE Mexico to E Ecuador and Venezuela Eisenmann (1955) O. guatemalae Vermiculated Tropical Middle America and Screech-Owl South America Wetmore (1968), Stiles and O. guatemalae Vermiculated NW and E Mexico to N Skutch (1979), Hilty and Screech-Owl Venezuela, W Ecuador and Brown (1986), Ridgely and Bolivia Gwynne Jr. (1989), Howell and Webb (1995) Hekstra (1982) O. guatemalae Vermiculated (19 subspecies, 6 of Screech Owl which were new including O. g. centralis) AOU (1998) O. guatemalae Vermiculated [guatemalae group] Mexico Screech-Owl to Nicaragua, [vermiculatus group] Costa Rica to W Colombia Dickinson and Remsen Megascops guatemalae Vermiculated Mexico to N Brazil and (2013) (9 subspecies) Screech Owl Bolivia Mikkola (2014) M. guatemalae Guatemalan Mexico to N Costa Rica (4 subspecies) Screech Owl M. vermiculatus Vermiculated Costa Rica to NW Colombia (2 subspecies) Screech Owl and N Venezuela M. centralis Chocó C Panama (Caribbean slope) Screech Owl to W Colombia and NW Ecuador 4 Vallely and Dyer (2018) M. guatemalae Vermiculated Mexico to South America Screech-Owl Holt et al.